You may want to call Dell to confirm, but in looking at what graphics options were available on these you are stuck with the Intel integrated video chipset. It is going go suck for gaming because it shares system ram. Looks like you got yourself a great business machine.

That being said, why not find a buddy with tf2 and give it a try to see if it will run at all. You may have to tweak the setting to minimum but it beats not playing at all.